Wednesday, March 5, 2014

Moas and barcoding

Moas were the dominant herbivores in New Zealand's forest, shrubland and subalpine ecosystems for thousands of years, and until the arrival of the Māori were hunted only by the Haast's Eagle an extinct raptor which is still considered the largest true raptor that ever existed. It is generally considered that most, if not all, species of moa died out by A.D. 1400 due to overhunting by the Māori and habitat decline. As a consequence the Haast's Eagle disappeared as well as his predominant prey was not available anymore.

Today we know there were at least nine species of moa endemic to New Zealand, but because the flightless bird died out hundreds of years ago due habitat decline and overhunting, it is challenging to gain a complete understanding of the birds, some of which could stand as high as 3.6 m with their necks fully extended.

Moa species can be grouped into six genera. One of these, Euryapteryx, has been difficult to characterize into its constituent species for a long time due to the absence of substantial morphological, physiological, and behavioral data.

Some researchers from New Zealand have now used DNA Barcoding to show that two species were likely to have existed in the genus Euryapteryx, with the possibility of some subspecies. However they also encountered some problems that could be explained with repeated hybridisation events within the genus:

Individuals from other areas of New Zealand were unable to be clearly separated based on COI differences possibly as a result of repeated hybridisation events. Despite the accuracy of the COI barcoding region to determine species status in birds, including that for the other moa genera, for moa from the genus Euryapteryx, COI barcoding fails to provide a clear result, possibly as a consequence of repeated hybridisation events between these moa. A single control region SNP was identified however that segregates with the two general morphological variants determined for Euryapteryx; a smaller subspecies restricted to the North Island of New Zealand, and a larger subspecies, found on both New Zealand's North and South Island.